In a case where the number of persons who intend to use a facility or a service exceeds the number of persons for which the facility is available or the number of persons to which the service is able to be offered, a waiting queue (hereinafter, called a queue) occurs. As queues, a queue for waiting to pay for fares at a supermarket checkout counter, a queue for waiting for tables at a restaurant, a queue for waiting to enter an art museum, a queue for waiting to go through security checks at an airport, a queue for waiting to use bathrooms, and so forth may be cited, for example. In many case, persons who stand in such queues wish to know how long the persons have to wait until facilities become available or until receiving services.
In the past, in order to inform persons who stand in a queue of waiting times, there has been proposed a method for image-capturing an image including the queue by using a camera, thereby informing of the waiting times, based on the image-captured image. In addition, there is proposed a method in which persons who stand in a queue register, in a server, standing in the queue and in which the persons are informed of a usage state of a facility, based on the number of persons registered in the server. As documents of related arts, there are Japanese Laid-open Patent Publication No. 2004-131389, Japanese Laid-open Patent Publication No. 7-287763, Japanese Laid-open Patent Publication No. 2002-329196, Japanese Laid-open Patent Publication No. 2004-38823, and Japanese Laid-open Patent Publication No. 2004-164507.